C++ Program to Implement the Bin Packing Algorithm

The bin packing problem is a special type of cutting stock problem. In the bin packing problem, objects of different volumes must be packed into a finite number of containers or bins each of volume V in a way that minimizes the number of bins used. In computational complexity theory, it is a combinational NP-hard problem.

When the number of bins is restricted to 1 and each item is characterized by both a volume and a value, the problem of maximizing the value of items that can fit in the bin is known as the knapsack problem.

Algorithm

Begin
   Binpacking(pointer, size, no of sets)
   Declare bincount, m, i
   Initialize bincount = 1, m=size
   For i = 0 to number of sets
   if (m - *(a + i) > 0) do
      m = m - *(a + i)
      Continue
   Else
      Increase bincount
      m = size;
      Decrement i
      Print number of bins required
End

Example Code

#include<iostream>
using namespace std;
void binPacking(int *a, int size, int n) {
   int binCount = 1;
   int m = size;
   for (int i = 0; i < n; i++) {
      if (m - *(a + i) > 0) {
         m -= *(a + i);
         continue;
      } else {
         binCount++;
         m = size;
         i--;
      }
   }
   cout << "Number of bins required: " << binCount;
}
int main(int argc, char **argv) {
   cout << "Enter the number of items in Set: ";
   int n;
   cin >> n;
   cout << "Enter " << n << " items:";
   int a[n];
   for (int i = 0; i < n; i++)
      cin >> a[i];
   cout << "Enter the bin size: ";
   int size;
   cin >> size;
   binPacking(a, size, n);
}

Output

Enter the number of items in Set: 3
Enter 3 items:4
6
7
Enter the bin size: 26
Number of bins required: 1